Given its track record of dam construction in the 20th Century, the Army Corps of Engineers may seem an unlikely source of good news for rivers. The Corps ultimately built nearly 700 dams across the nation, including some major ones in the West. (The chapter in Cadillac Desert describing the Corps’ competition with the Bureau of Reclamation to build dams in the western states is titled “Rivals in Crime.”) Although flood control is the main purpose of Corps dams generally, they also generate hydropower, support navigation, and provide flatwater recreation, among other things. There is also growing interest in Corps reservoirs (not only in the West) as potential sources of water supply.

Dams can harm rivers in many ways, so it is not surprising that the Corps has a reputation for riparian destruction. Starting in the 1980s, however, Congress began giving the Corps authority and direction for environmental restoration efforts; today, the Corps clearly wants to be known as an agency that does good things for aquatic ecosystems. Among other things, the Corps maintains an Environmental Advisory Board (EAB), composed mostly of scientists from universities across the country. The efforts of the EAB led to the Corps making a decision that looks like good new for rivers below Corps dams.

The EAB wrote to the commanding officer of the Corps in 2014, recommending that the Corps “initiate environmental flows from as many of its dams as possible.” The letter described environmental flows as “releases from dams and their reservoirs to create downstream river flows that create the conditions needed to sustain freshwater ecosystems.” It also recommended that the Corps take three specific actions toward providing environmental flow releases from more dams. The letter was backed by an eight-page report that explained the EAB’s rationale and recommendations in greater detail.

Nineteen months elapsed … but when the response came in a November 2015 letter, it was positive. The Corps largely accepted the EAB’s recommendations, and identified steps the agency would take (or was already taking) to carry them out. While much of the letter covers bureaucratic details, the opening two paragraphs address the big picture:

[T]he Corps is increasingly being asked to assess how the Nation’s rivers and waters might be managed differently to provide more environmental benefits, while concurrently providing for navigation, flood risk management, hydropower, recreation, and water supply. Further, the Corps is under pressure to complete work with shorter schedules and less funding, and when our largest and most expensive environmental efforts are driven by litigation and endangered species.

It is precisely at these times that we need to aggressively and proactively pursue ideas like implementation of environmental flows, which have high environmental potential for relatively low costs.

Thus, the Corps not only views environmental flows as a practical way to improve rivers, but also sees real value in having the agency’s environmental restoration efforts not be driven entirely by the requirements of the Endangered Species Act.

Since the Corps made this statement less than a year ago, much remains to be seen about its implementation. Will the Corps proceed to revise its operating practices to provide environmental flows on more rivers? That will be an especially important question in the West, where flows often fall below environmental needs, but water supply concerns are typically paramount, and most state water laws and institutions give low priority to environmental flows. So while rivers across the country will be waiting to see what the Corps does, for now it deserves credit for what it says about environmental flows.